The present invention relates generally to air systems for fluid jet devices. More particularly, the present invention pertains to air systems to prevent debris from interfering with the proper operation of fluid jet devices, such as ink jet print systems.
Fluid jet devices are in wide spread use. One particular use for such devices is in ink jet printers. There area number of principle types of ink jet printers. One type of printer relies upon capillary action to move a working fluid (e.g., ink) to the print head. The ink is directed from the print head through one or more orifices toward a target substrate. Ink jet printers include an actuator for urging the ink through the orifice. Actuators can include piezzo electric elements, thermal devices and the like. An exemplary ink jet print head is disclosed in DeYoung et al., U.S. Pat. No. 4,418,355.
The ink is ejected from the print head as a droplet of fluid. These droplets are extremely small in volume and mass. In that many such operations are carried out in commercial or industrial environments the processes are potentially subjected to dust and debris. For example, the printing is often applied to boxes or other shipping containers carried on a conveyor or line within a manufacturing facility. To this end, the potential for dust and debris to disrupt or interfere with the printing operation is quite high.
A number of devices, configurations and methods have been proposed and are used to prevent the introduction of dirt and debris to the inkjet print head and into the ink droplet path. For example, air knives, air curtains, blow off nozzles and air blankets are designed to alleviate dust and debris around the print heads. However, these devices are manufactured as part of the print head. As such, they are relatively costly, and cannot be retrofitted to existing inkjet system.
Moreover known systems typically operate at high pressures, on the order of about 30 to 80 pounds per square inch (psi). Even the known lower pressure system, generally operate at pressures of about 30 psi or greater. These high pressure systems can adversely effect printing by action of the high pressure air interfering with the ink droplet pattern.
Accordingly, there exists a need for an air system for inkjetting devices that reduces the potential for dust and debris interfering with the jetting pattern. Desirably, such a system effectively forces debris from an article that is to have the jetted fluid applied thereto. More desirably, such a system effectively envelopes the environment around the jetted fluid to prevent the ingress of outside dust and debris into the local environment. Most desirably, such a system minimally, if at all, adversely interferes with the jetted fluid.